Five Democratic presidential candidates have told a black foreign affairs publication that they would significantly alter U.S. policy in Africa and the Caribbean, with Sen. Alan Cranston (Calif.) saying he would extend diplomatic recognition to Cuba.

Sen. Ernest F. Hollings (S.C.) said he would impose comprehensive economic sanctions on South Africa. Cranston, Sen. John Glenn (Ohio) and Sen. Gary Hart (Colo.) also said they would initiate action to recognize the Marxist government of Angola.

Their comments are contained in a special issue of the journal TransAfrica Forum to be released today by TransAfrica, a Washington-based organization that does research and lobbies on foreign-policy issues of significance to blacks.

Black politicians, civil rights leaders and special-interest groups are pitching U.S. policy in the Third World as a potential issue in the 1984 campaign.

For instance, a 119-page "People's Platform" endorsed last week by several national politicians and civil rights leaders who urged a black to seek the Democratic presidential nomination criticized U.S. foreign policy as "increasingly bellicose, racist and interventionist."

That theme often was echoed in statements to TransAfrica Forum by the five candidates, who denounced Reagan administration actions in Africa and the Caribbean as ineffective, divisive, militaristic and distorted by what they said is a tendency to cast all foreign policy in Cold War terms.

Last Thursday, Lawrence S. Eagleburger, undersecretary of state for political affairs, reaffirmed the administration's view that apartheid is "morally wrong" and that the administration is working to change it. His speech was billed as a major rebuttal to criticism that the administration is soft on South Africa.

In many instances, views presented by the five Democrats suggest a foreign policy in the two regions more liberal than that of the last Democratic administration.

Randall Robinson, executive director of TransAfrica, said he thinks that is a result of "recognition of blacks having increasing clout in Democratic elections."

President Carter, for instance, moved toward normalization of ties with Cuba, provided that the two countries could resolve concerns about Cuba's role abroad, its domestic human relations and $3 billion in U.S. claims stemming from nationalizations by the Cuban government. None was resolved.

Cranston is quoted in the journal as saying, " . . . We certainly should begin a process aimed at establishing relations with Cuba. The fact that we abhor many of Cuba's domestic and foreign policies is no excuse for withholding recognition from this country so close to our shores."

Cranston's campaign press secretary, John Russonello, asked if Cranston's statement should be read as a return to the Carter position, said Friday, "Recognition of Cuba is the first step to working out our differences, to solving the problems between our two nations. There would be no preconditions."

Hollings is quoted in the interviews as opposing recognition as long as Cuban troops are in Angola. Glenn, Hart and former vice president Walter F. Mondale generally favored some dialogue toward recognition.

Presidents Carter and Reagan declined to recognize Angola. Cranston, Hart and Glenn said the United States could benefit from recognition, while Mondale simply urged more dialogue on possible recognition.

African states long have advocated U.N. imposition of comprehensive economic sanctions against South Africa as a way to force a change in apartheid policies.

That approach is considered impractical by many who contend that western nations are too reliant on South Africa for minerals and that too many U.S. companies operate there.

The candidates were asked if they would endorse sanctions.

"Yes, at this point I would support such sanctions," Hollings said. "Economic sanctions are not a desirable policy of first choice. The present situation, however, leaves us with few alternatives."

The others said they would be willing to use the threat of comprehensive sanctions, and other tactics, to prod South Africa into changing its policies.

Cranston suggested embargoes of air traffic and shipments of nuclear material. Glenn said he would discourage new U.S. investment and promote advancement of blacks in South Africa.

Hart urged legislation requiring U.S. firms there to engage in fair employment and wage practices. Mondale called for improving relations with other African nations, saying they have worsened under Reagan.

All five generally favored more developmental aid for Africa and said they would emphasize the role of regional organizations in resolving disputes between African nations.

The article also contains responses of the five to questions on Reagan's Caribbean Basin Initiative, U.S. policy toward Grenada and Nicaragua, and revision of immigration laws.

Robinson said former Florida governor Reubin Askew, the sixth announced Democratic candidate, is to submit answers to the eight questions for publication later.